In the production of yarns in open-end spinning machines, it is necessary to, depending on the type of the fiber material to be spun and depending on the type of the desired yarn to be manufactured, use different spinning rotors or spinning rotors with different rotor cups, since the shape and the design of the rotor cups of the spinning rotor have a significant effect on the spinning result. Given the permanent contact with fiber, the rotor cups of spinning rotors in open-end spinning machines are also subjected to significant wear, and therefore must be replaced. Depending on the structure of the open-end spinning device and the bearing of the spinning rotor, the replacement of the spinning rotors can be associated with a significant effort, such that spinning rotors are often provided with a coupling device for replacing the rotor cup. Particularly in open-end spinning devices in which the rotor shaft is mounted in a magnetic bearing, the installation or removal of the complete spinning rotor is expensive, such that spinning rotors with a coupling device are typically employed.
DE 38 15 182 A1 describes a spinning rotor with such a coupling arrangement. Thereby, DE 38 15 182 A1 provides for arranging a coupling shell with a recess or a sleeve at the end of the rotor shaft; a corresponding complementary designed pin, which is arranged on the reverse side at the bottom of the rotor pot, engages in this. The transmission of the turning moment from the rotor shaft to the rotor pot should thereby take place through a positive-locking connection of both coupling parts with each other. According to a second embodiment, in place of a large, central pin, several smaller pins that engage in recesses of the coupling shell can also be provided. A permanent magnet, which is inserted into the coupling disk on the rotor shaft, is used to hold the rotor pot. The coupling arrangement is relatively costly to produce, and also relatively large and heavy, which is disadvantageous with today's high rotational speeds.
EP 1 156 142 B1 shows a spinning rotor that is already provided with a magnetic bearing arrangement for an open-end spinning device. The coupling device includes a shaft sleeve arranged on the shaft of the spinning rotor, in which an internal hex is arranged. A cylindrical guiding collar is formed on the rotor cup as a coupling device; this engages in the shaft sleeve of the rotor shaft. In the extension of the cylindrical guiding collar, there is an external hex that engages in the internal hex in the shaft sleeve of the rotor shaft. Behind the shaft sleeve of the rotor shaft, which includes the internal hex, a permanent magnet is likewise arranged within the rotor shaft; this is to take over the axial securing of the coupling device. The production of the spinning rotor with the additional guiding collar and the additional shaft sleeve is likewise relatively expensive.